10 replies to this topic

[GauravChachra]

Me and my father are about to setup a small scale factory of manufacture of liquid soap, like Dettol Hand Care soap. I am still in the final year of Bachelor of Engineering course in Chemical Engineering.

I want to know what resource can I use to know the materials of construction for pumps, valves, pipes etc. that will be compatible for long life with my raw materials and product streams. Can you suggest any book that specifically focuses on material of construction.

Also, what kind of pump would you suggest for a product stream of viscous liquid like Liquid Hand Soap. Please, if possible give appropriate reasons.

Thanks a lot!

[Art Montemayor]

You can't expect a specific response when you don't give specific information.

You have failed to tell us what specific chemicals or fluids you are dealing with - and their chemical composition, temperature, pressure, etc. So we can't give you specifics.

The Gould's GPM pump catalog had an excellent table of many chemicals and the recommended materials of construction. You can download this material from the internet at the Goulds Pump website site. There are many other sources of information - like the old Ingersoll-Rand pump databook. Other forum members will probably offer other sources of information.

I don't believe you are going to be successful in using a centrifugal pump to move a highly viscous fluid (absolute viscosity = unknown). You will probably have to rely on a screw type or lobe type of pump. But you should rely on the fabricators recommendations, not ours, for the specific use and model.

[pawan]

Consider Corrosion Handbook.

[GauravChachra]

Well.. Thanks for your reply. Basically we prepare the product by a reaction between an acid 'Linear Alkyl Benzene Sulphonic Acid' and 'Caustic Soda' (NaOH) plus some salts. So the product is basically a neutral liquid detergent with pretty ordinary temperature condition of 30-50 degrees C and a moderate head of about 10-15 ft required from the pump. Viscosity is similar to that of any hair shampoo (though we've not got it tested for exact value yet).

So if you could now suggest any construction material and pump type for a hair shampoo kind of material, it'll be great!
From the Goulds Pump Guide it seems Stainless Steel is suitable.

Thanks a lot.

[Profe]

Hi GauravChachra

I think that you have to review the Chemical Engineer´s Handbook by Perry and Greene, chapter 28. The subject of this chapter deals about construction materials for chemicals plants, parts and pieces of equipment

Good luck

[Art Montemayor]

From what you describe, I would try a standard material of construction: Cast Iron

If you want to spend the extra money for stainless steel, that is your decision.

We still can't respond with specifics when all you have furnished are generalities.

I hope this helps.

[pawan]

We are using similar kind of reactions for other products. In case of LABSA, we prefer SS-316 as a perfect MOC.

[srtools1980y]

hi!
refer ''corrosion resistance tables'', philip a. schweitzer, marcel dekker pub.
regards.

[JEBradley]

Because of the nature of your liquid (A healthcare product) you should be looking to use stainless steel. SS 316 is best but I see no reason why SS 304 couldn't be used (it's less expensive).

As for the type of pump, a centrifugal pump could be used as the viscosity isn't too high - that is to say, the viscosity of dettol wouldnt be a problem, however some modern shampoos have much much higher viscosities and complex rheology so a little bt of investigation would be required here.

Just a thought - be aware your product will foam and ensure you can eliminate any risk of air entrainment into the system. I hope i'm not dragging this thread off at a tangent but perhaps someone could suggest ways to prevent this happening. Normally I would add a small amount of anti-foam but obviously in your case you still want the product to foam at the end of the day.

[Art Montemayor]

JE:

I believe that if you check the availability and the price difference between 304SS and 316SS construction for such items as control valves, piping, pump casings, exchanger tubing, etc. , you will find that 316SS is less expensive and more available.

About 30 years ago, manufacturers finally got tired of stocking up both types of stainless construction and woke up to the fact that even if 316SS was initially more expensive, if they standardized their fabrication on one type (316SS), it would be cheaper for them - and for the purchaser. That is what the greatest majority of fabricators did in the USA and Stainless Steel items immediately fell in price and went up in availability - in the 316SS type, of course. Mass production in volume and less warehouse inventory was a direct contribution to this effect. At one time, I specified 304SS for a control valve only to find that I paid more money (& had a longer delivery) than if I had settled for 316SS.

I would expect the same in the U.K. and would like to hear some feedback on this from others on the Forums.

[djack77494]

I would expect the same in the U.K. and would like to hear some feedback on this from others on the Forums.

Art,
I believe what you say is true. In fact, I would extend the concept a bit by noting that in the past we made a distinction between 304 & 304L SS and 316 & 316L SS. Sometime back I had written that I needed an item made of 316 and was asked if it would be acceptable to substitute 316L. I was puzzled until told that the 316L part would actually cost less than the 316 part. In fact, my understanding today is that there really are no 304 & 316; they are all formulated to the low carbon specs. Again, though, I would welcome comments from others on this topic.
Doug